A water well typically includes casing, i.e. metal tubing extending down at least the top portion of the well. This casing typically has a rough top surface that can cause some problems during pump installation and afterward. Specifically, pump installation entails lowering a pump into a well by a set of insulated wires that will power the pump after it is installed. If the wires are permitted to rub against the rough top of the casing, they may abrade away the insulation, leaving bare wire that can then short out against the conductive casing and the water, thereby creating an electric shock hazard. Accordingly, the job of the pump installer is made more difficult by the need to hold the insulated wires away from the casing as the pump and wires are lowered into the well.
Even after the pump has been installed, the wires may be left in such a manner that they will rub against the top of the casing. This, together with vibrations induced either by operation of the pump or by some nearby source can eventually cause the insulation to be abraded away, exposing the bare wires.